Last night's Fringe episode featured one truly great scene, where Olivia looked at the junkyard prophet played by Jill Scott, and explained that she, too, had extraordinary abilities and had seen amazing things. But this was thanks to science, and didn't mean anything else. Olivia concluded with a terrific line: it's all just numbers, and the invaders are better at math than we are.

And just like that, I was interested in Olivia as a character, for the first time this season. Until the show felt a need to have her do a 180. Spoilers ahead...

Olivia's viewpoint and the junkyard psychic's are both valid, of course — but I liked that Olivia stood up for science and materialism. And it made sense that Olivia, whose psychic powers were a gift not from God but from Walter Bishop (slight difference), would reject the idea of "gifts" and blessings and so on.

Jill Scott is a fantastic singer — her song "It's Love" is on endless replay at my house — but man did she creep me out as a sweet church lady who's been waiting 21 years in a junkyard for Olivia to show up and take Walter's magnet away. It's something about the way she keeps smiling like she's doing the will of Landru. In any case, using her psychic powers, she figures out that Olivia lost her daughter — twice — and tells Olivia that Etta is still with her.

Later, Olivia is driving the magnet back to Boston, when she gets ambushed by two guys, one of whom wants to turn her in for the reward. Olivia manages to escape, in a way that convinces her that Junkyard Psychic Lady was right and Etta is still with her.

(Actually, no — Olivia's escape is proof that Olivia is a smart, resourceful person who can improvise a death trap out of whatever parts she has laying around, thanks to years of experience and FBI training. True, the bullet Etta gave her was a key ingredient in that deathtrap, but she would have figured out something else. Her escape is also proof that tying someone up with a tiny amount of rope in a room full of sharp edges and then leaving her unguarded is a flawed strategy at best.)

In any case, if this whole "Olivia goes from being a doubter to a believer in 60 seconds flat" storyline feels rushed, that's because it's not about Olivia at all. Like everything else this season, it's about Peter.

The purpose of this episode is to wrap up the "Peter gets Observer powers" storyline that started a few episodes ago, and put all the toys neatly back in the box. As soon as the promo at the end of the previous episode showed Walter saying that Peter's transformation could soon be irreversible, it was obvious that this episode would be about them reversing it in the nick of time. With, probably, no lasting consequences.

We do get to see a neat computer model of how the Observer tech changes the human brain — basically, adds more ridges — and Walter gets to do some of his trademark zany brain science. But the main thing Walter learns, that the Observers are super-smart and have almost no emotion, is something we pretty much knew already.

In any case, there are some good arguments against what Peter is doing. First, he's gained a (probably temporary) strategic advantage — but he's only one quasi-Observer, against an army of Observers. Second, killing Windmark might be satisfying, but Windmark is just one stooge. He's of limited strategic value, and his death changes nothing in the long term. The system killed Etta, not just Windmark. Third, you have to assume that September saved Peter — twice — for a reason, and not just so that Peter could become another Observer.

In any case, the point of Olivia deciding that the Junkyard Prophet was right after all, is so that she can pop up just as Peter is initiating his Wile E. Coyote-esque plan to defeat Windmark (who kicked Peter's butt not long earlier) and talk him out of it. In a nutshell, Olivia says that Etta is still with her and that Etta saved her life not long earlier. And Olivia makes the not-unreasonable point that if Peter becomes an emotionless monster, he'll have forgotten Etta, and then she'll really be gone. (Earlier in the episode, we saw all the Etta-themed "RESIST" posters finally being pulled down, after weeks of being left up.)

This leads to Peter pulling out a penknife and doing some impromptu rooftop brain surgery with it. Which was my other favorite moment in the episode, just because we don't see brain surgery done with a penknife often enough. (Admittedly, he didn't actually have to go into the brain, just yank out the handy protruding tail of the Observer implant.)

All in all, this was an okay conclusion to the "Peter becomes an Observer" mini-arc. The point of it all seemed to be that grief can make you shut down and turn off your emotions. And that revenge can turn you into a monster. And that you shouldn't become the thing you're trying to fight. All of which are perfectly good morals for a storyline to have. I just wish Peter's time as an Observer had left the status quo slightly different. And that we could get a storyline that's actually about Olivia, rather than using her as a prop for Peter's storylines. Maybe next week?